Regulators in the USA have given another green light to GlaxoSmithKline’s Promacta, this time for a rare bone marrow disorder.

The  Food and Drug Administration has approved a supplemental New Drug Application for the once-daily use of Promacta/Revolade (eltrombopag) in patients with severe aplastic anaemia (SAA) who have had an insufficient response to immunosuppressive therapy. SAA is a disorder where the bone marrow fails to make enough red blood cells, white blood cells, and platelets.

Promacta, which is partnered with Ligand Pharmaceuticals and is already approved for thrombocytopenia, gained breakthrough therapy designation status for SAA from the FDA in January and was granted a priority review in April. The approval is based on results from a 43-patient Phase II study conducted by the National Institutes of Health which demonstrated a haematologic response in SAA patients treated with the drug who had not responded to immunosuppressive therapy (IST).

Paolo Paoletti, head of oncology at GSK, said that through collaboration with the NIH, “whose studies demonstrate the potential for Promacta to achieve a haematologic response in at least one lineage – red blood cells, platelets, or white blood cells – patients now have a treatment option where one didn’t previously exist

In the USA, 300 to 600 new cases of SAA are identified each year. Of patients treated with IST, one-quarter to one-third will not respond and 30-40% of responders will relapse. Some 40% of SAA patients who do not respond to initial IST die from infection or bleeding within five years of their diagnosis.